Low-irritation compositions and methods of making the same

ABSTRACT

Provided are compositions comprising a low molecular weight, non-crosslinked, linear acrylic copolymer and at least one surfactant selected from the group consisting of anionic surfactants, amphoteric surfactants, and combinations of two or more thereof, and methods of using such compositions.

FIELD OF INVENTION

The present invention relates to compositions having low irritationcharacteristics in combination with one or more additionalcharacteristics, for example, relatively high clarity, relatively highfoaming, and/or combinations thereof, as well as methods of making andusing such compositions.

DESCRIPTION OF THE RELATED ART

Synthetic detergents, such as cationic, anionic, amphoteric, andnon-ionic surfactants, are used widely in a variety of detergent andcleansing compositions to impart cleansing properties thereto. Inaddition, in certain compositions (e.g. personal care compositions suchas shampoos, washes, etc.), it may be desirable to use combinations andlevels of surfactants sufficient to achieve relatively high levels offoam volume and/or foam stability.

However, as is recognized in the art, synthetic detergents tend to beirritating to the skin and eyes. Thus, as levels of such detergents areincreased in attempts to increase cleansing and foaming propertiesassociated with certain compositions, the irritation associated withsuch compositions also tends to increase, making them undesirable foruse on or near the skin and/or eyes.

Certain attempts to produce milder cleansing compositions have includedcombining relatively low amounts of anionic surfactants (which tend tobe relatively high-foaming but also relatively highly irritating), withrelatively lower irritating surfactants such as nonionic and/oramphoteric surfactants. See, e.g. U.S. Pat. No. 4,726,915. Anotherapproach to producing mild cleansing compositions is to associate theanionic surfactants with amphoteric or cationic compounds in order toyield surfactant complexes. See, e.g., U.S. Pat. Nos. 4,443,362;4,726,915; 4,186,113; and 4,110,263. Disadvantageously, mild cleansingcompositions produced via both of such methods tend to suffer fromrelatively poor foaming and cleansing performance.

Applicants have further recognized that for certain uses it is desirablefor cleansing compositions to be relatively clear. In particular, clearcompositions are often used advantageously to provide an aestheticindication of purity to the consumer. However, applicants haverecognized that the use of various ingredients in conventionalcleansers, including, for example, polymeric thickeners, tend to resultin cloudy or opaque compositions. Thus, it is not readily predictablewhich combinations of polymers, surfactants and other optionalingredients may be combined to create compositions that are suitable foruse as cleansers and also exhibit high clarity.

Accordingly, applicants have recognized the need for compositions thatare not only mild to the skin and/or eyes, but additionally exhibitrelatively high clarity, desirable foam properties and/or otherdesirable aesthetic properties.

SUMMARY OF THE INVENTION

The present invention provides mild cleansing compositions and methodsof reducing the irritation associated with a variety of personal carecompositions, which compositions and methods overcome the disadvantagesof the prior art. In particular, according to certain preferredembodiments of the present invention, applicants have discoveredadvantageously that non-crosslinked, linear acrylic copolymer materialscapable of binding surfactant thereto can be used to produce personalcare compositions exhibiting surprisingly low irritation to the skinand/or eyes. In certain embodiments, the mild compositions of thepresent invention additionally exhibit relatively high clarity,high-foaming/foam stability properties, and/or unique viscositycharacteristics, as compared to compositions comprising comparable,polymeric materials.

According to one aspect, the present invention provides for compositionscomprising a non-crosslinked, linear acrylic copolymer and at least onesurfactant selected from the group consisting of anionic surfactants,amphoteric surfactants, nonionic surfactants and combinations of two ormore thereof.

According to another aspect of the present invention, provided aremethods of reducing the irritation associated with a compositioncomprising an anionic, amphoteric, and/or nonioniic surfactant, themethod comprising combining a non-crosslinked, linear acrylic copolymermaterial with at least one surfactant selected from the group consistingof anionic surfactants, amphoteric surfactants, and combinations of twoor more thereof.

According to yet another aspect of the present invention, provided aremethods of cleansing a portion of the human body with reduced irritationthereto comprising the step of contacting the body of a mammal with areduced irritation composition comprising an anionic and/or amphotericsurfactant and a non-crosslinked, linear acrylic copolymer material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphical depiction of the relative ability of polymers ofone embodiment of the present invention, a comparable low-molecularweight polymer, and a comparable higher molecular weight polymer, toassociate surfactants thereto.

FIG. 2 is a graphical depiction of the idealized tensiometry dataassociated with the addition of anionic surfactant to two solutions.

FIG. 3 is a graphical depiction of the tensiometry data associated witha composition of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

As used herein the term “low molecular weight” polymer refers to apolymer having a number average molecular weight (M_(n)) as measured bygel permeation chromatography (GPC) calibrated with a poly(methylmethacrylate) (PMMA) standard of about 100,000 or less. In certainpreferred embodiments, low-molecular weight polymers are those havingmolecular weight ranges of from about 5,000 to about 80,000 M_(n), morepreferably from about 10,000 to about 50,000 M_(n), and more preferablybetween about 15,000 and 40,000 M_(n).

Applicants have herein discovered that the compositions of the presentinvention exhibit a unique and unexpected combination of propertiesincluding relatively low irritation, and preferably including bothrelatively low irritation and relatively high clarity. In particular,with respect to low-irritation, applicants have measured the relativeefficiency in binding surfactant, C90, Delta CMC, TEP, and Delta TEP (asdefined herein) of the compositions of the present invention anddiscovered that they tend to be significantly better than compositionscomprising comparable commercially available polymers having arelatively high molecular weight, and at least as good as compositionscomprising other low molecular weight polymers. For example, shown inFIG. 1 is a graph 10 of the relative ability of polymers of oneembodiment of the present invention (curve 11), a comparablelow-molecular weight polymer (sold under the Tradename “Inutec SP-1” byOrafti, curve 12), and a comparable higher molecular weight polymer(sold as Carbopol Aqua SF-1 by Noveon, curve 13), to associatesurfactants thereto. Such ability was measured by calculating the DeltaCMC associated with the polymer and surfactant using the ForwardTitration Tensiomtry Test, as described below wherein higher Delta CMCindicates higher association of surfactant to polymer, and the Delta CMCplotted as a function of polymer concentration to illustrate therelative efficiency of the polymers of the present invention inassociating the surfactant. As seen in FIG. 1, the polymer of thepresent invention tends to associate surfactant efficiently atrelatively low concentrations and, in particular, tends to besignificantly and unexpectedly efficient in associating surfactant atrelatively higher concentrations as compared to the comparativepolymeric materials shown.

Although applicants do not wish to be bound by or to any particulartheory of operation, it is believed that the polymeric materialssuitable for use in the instant methods act to reduce the irritationassociated with personal care compositions, at least in part, by bindingsurfactant (free (unbound) surfactant molecules and/or, especially,surfactant free (unbound) micelles) thereto to reduce the concentrationof irritation-causing free micelles available in the composition toirritate the skin and/or eyes. That is, applicants have recognized thatthe relative amounts of surfactant free micelles contained in aparticular composition affect the relative irritation to the skin and/oreyes associated with that composition, wherein higher amounts of freemicelles tend to cause higher levels of irritation and lower levels offree micelles tends to cause less irritation. By binding surfactantand/or surfactant micelles thereto, the polymeric materials reduce theconcentration of unbound surfactant micelles in a composition and allowfor a higher concentration of surfactant to be added to the compositionbefore free micelles are formed and/or before a particular level ofirritation is achieved. This desirable shift in the concentration ofsurfactant required prior to the formation of free micelles isillustrated further in FIG. 2.

FIG. 2 is a graph 20 showing the idealized surface tension data curvesassociated with the addition of anionic surfactant to two compositions,a composition comprising a polymeric material of the present inventionand a comparable composition composition free of polymeric material.Curve 21 shows the change in surface tension, measured via conventionaltensiometry techniques (examples of which are described hereinbelow), ofa composition free of polymeric material as increasing levels of anionicsurfactant are added thereto. Curve 25 shows the change in surfacetension of a composition comprising polymeric material as increasinglevels of anionic surfactant are added thereto. In curve 21, assurfactant is added to solution, the surfactant tends to populate theliquid/air interface, thus reducing the surface tension of the solution,until essentially the entire surface area is filled. After this point,hereinafter the “critical micelle concentration (CMC)” of surfactant,point 22, essentially all surfactant added to the composition forms freemicelles in solution, which formation does not have an appreciableaffect on the surface tension of the solution, but tends to increase theirritation associated with the composition. By comparison, as shown incurve 25, as anionic surfactant is added to a solution comprising apolymeric material of the present invention, the surfactant both alignsitself on the liquid/air interface and binds to the polymeric materialuntil the CMC, point 26, shifted to a significantly higher surfactantconcentration as compared to curve 21, at which point the surfactantadded tends to form free micelles.

In light of the above, applicants have recognized that one measure ofthe efficacy of a particular low molecular weight polymeric material inbinding surfactant thereto may be expressed as the “Delta CMC” achievedby combining the polymeric material with an anionic surfactant to form areduced irritation composition. A “Delta CMC” as used herein is definedas the number obtained by: (a) determining the CMC for: (i) a particularcomposition of the present invention comprising anionic surfactant andpolymeric material, and (ii) the “comparable composition” of thecomposition in (i), which CMC values are determined using either theForward or Reverse Titration Tensiomtry Test procedures defined in theExamples below; and (b) subtracting the CMC value obtained forcomposition (ii) from the value obtained for composition (i). As usedherein, the “comparable composition” of a particular compositioncomprising anionic surfactant and polymeric material means a compositionwhich consists of the same components in the same relative weightpercents as the anionic surfactant/polymeric material composition withthe exception that the polymer of the anionic surfactant/polymericmaterial composition is replaced in the comparable composition with thesame relative weight percent of water. For example, the comparablecomposition for an anionic surfactant/polymeric material compositionconsisting of 7% anionic surfactant, 15% amphoteric surfactant, 5% lowmolecular weight polymer, 5% glycerin, and 68% water (wherein allpercents are by weight based on the total weight of the composition) isa composition consisting of 7% anionic surfactant, 15% amphotericsurfactant, 5% glycerin, and 73% water. By way of further example, thecapability of a particular polymer material to bind a particularsurfactant thereto in accord with the present invention may also bereadily determined by measuring the CMC values of a compositioncomprising just the polymeric material and the surfactant in solution(for example, 12% surfactant/3% low molecular weight polymer/85% water)and a comparable composition comprising just the surfactant in solution(for example, 12% surfactant/88% water) and subtracting the latter fromthe former to get a Delta CMC.

Applicants have now discovered that combinations of non-crosslinked,linear acrylic copolymer materials with anionic, nonionic and/oramphoteric surfactants, preferably at least one anionic and/oramphoteric surfactants, tend to result in significant positive delta CMC(and thus significant reduction in irritation) that is at least as good,if not better than the delta CMC (and reduction of irritation)associated with the addition of comparative polymers. In certainembodiments, it is preferred to select a non-crosslinked, linear acryliccopolymer material for use in the present methods such that the DeltaCMC measured using the Reverse Titration Tensiomtry Test associated withthe resulting reduced irritation composition is a positive value. Incertain more preferred embodiments, the non-crosslinked, linear acryliccopolymer material is selected to achieve a reduced irritationcomposition having a Delta CMC measured using the Reverse TitrationTensiomtry Test of about +80 or greater, more preferably, about +100 orgreater, even more preferably of about +120 or greater, even morepreferably of about +200 or greater, and even more preferably of about+300 or greater. In certain other preferred embodiments, thenon-crosslinked, linear acrylic copolymer polymer for use in the presentinvention is one which results in a Delta CMC measured using the ReverseTitration Tensiomtry Test of about +400 or greater, more preferably,about +450 or greater, even more preferably of about +500 or greater,and even more preferably of about +600 or greater.

Applicants have recognized that the “TEP value” associated with aparticular composition, which value is measured conventionally via theTrans-Epithelial Permeability Test (“TEP Test”) as set forth in theInvittox Protocol Number 86 (May 1994) incorporated herein by referenceand described in further detail in the Examples below, has a directcorrelation to the irritation to the skin and/or eyes associated withthe composition. More specifically, a higher TEP value of a compositiontends to indicate less irritation to the skin and eyes associatedtherewith as compared to a composition having a lower TEP value, whichcomposition tends to cause higher levels of irritation to the skinand/or eyes. Applicants have recognized that the present methods aresuitable for producing personal care compositions having relatively highTEP values/lower irritation associated therewith. For example, incertain embodiments, the present methods produce compositions having aTEP value of at least about 1.5 or greater. In certain more preferredembodiments, the composition produced according to the present methodsexhibit a TEP value of at least about 2 or greater, more preferably, atleast about 2.5 or greater, even more preferably, at least about 3 orgreater, and still more preferably, at least about 3.5 or greater. Incertain particularly preferred embodiments, the compounds exhibit a TEPvalue of at least about 4.0 or greater, and even more preferably, about4.5 or greater.

Furthermore, to determine when, and to express the degree to which, acomposition comprising an anionic surfactant and polymeric materialproduced via the present methods exhibits reduced irritation incomparison to a comparable composition free of the polymeric material,applicants herein define the term “Delta TEP” of a composition of thepresent invention as the value obtained by: (a) measuring the TEP valuesof: (i) the composition of the present invention comprising an anionicsurfactant and polymeric material and (ii) the comparable compositionfor such composition; and (b) subtracting the TEP value of thecomparable composition from the TEP value for the anionicsurfactant/polymeric material composition. Certain preferred reducedirritation compositions of the present invention include those having aDelta TEP of at least about +0.5. Certain more preferred reducedirritation compositions include those having a Delta TEP of at leastabout +0.75, and more preferably at least about +1. Certain particularlypreferred reduced irritation compositions include those having a DeltaTEP that is at least about +1.2, more preferably at least about +1.5,and more preferably at least about +1.8.

As indicated above, applicants have discovered that a positive shift inCMC correlates to a higher TEP and lower irritation associated with acomposition. Accordingly, as used herein the term “reduced irritationcomposition” refers generally to a composition comprising an anionicsurfactant and one or more polymeric materials capable of bindingsurfactant thereto, which composition has a positive Delta CMC measuredusing the Reverse Titration Tensiomtry Test and a positive Delta TEPvalue (i.e. the composition has higher TEP value than its comparablecomposition), measured via the Invittox Protocol incorporated herein.Certain preferred reduced irritation compositions exhibit combinationsof the preferred Delta CMC and Delta TEP values disclosed above (andinclude any combinations of preferred, more preferred, and even morepreferred values of at least one Delta CMC and at least one Delta TEP).

Applicants have further recognized that the present invention allows forthe production of compositions that exhibit not only reduced irritation,but also desirable clarity, rheology and/or foaming properties. Inparticular, applicants have measured the clarity of the presentcompositions (via the Clarity Test described herein below, wherein ahigher percent transmittance relates to a composition that is clearerthan a composition having a lower percent transmittance) and theturbidity of the compositions (via the Turbidity Test described hereinbelow, wherein a lower NTU value relates to a composition that isclearer than a composition having a higher NTU value) and havediscovered unexpectedly that such compositions have an unexpected andrelatively high clarity as compared to comparable compositionscomprising other low molecular weight polymers and/or high molecularweight polymers. For example, applicants have discovered that in certainembodiments the present compositions exhibit a clarity that is up toabout 2.6 times or more greater than comparable compositions. In certainpreferred embodiments, the present compositions exhibit a clarity asmeasured via the Clarity Test of at least about 90% transmittance. Incertain more preferred embodiments, the present compositions exhibit aclarity at least about 93% transmittance, more preferably at least about95% transmittance, more preferably at least about 97% percenttransmittance, and in certain preferred embodiments at least about 98%.In certain embodiments, the present compositions exhibit a turbiditythat is less than about 100 NTU, more preferably less than about 50 NTU,more preferably less than about 20 NTU, more preferably less than about10 NTU, and in certain preferred embodiments less than about 5 NTU.

In addition, applicants have discovered that while certain highermolecular weight polymers tend to increase the viscosity and the yieldpoint associated with a composition as more polymer is added, thepolymers of the present invention tend to have relatively small effecton the rheology of the compositions to which they are added.Accordingly, in certain embodiments, higher amounts of the presentpolymers may be added to more significantly reduce irritation withoutproducing a composition that is too viscous for effective personal use.

The polymeric material for use in the present compositions is preferablya composition suitable for associating anionic and/or amphotericsurfactant thereto and is a non-crosslinked, linear acrylic copolymerthat mitigates the ocular and dermal irritation typically associatedwith surfactant systems without substantially increasing viscositybuild. The non-crosslinked, linear polymers are preferably of lowmolecular weight having a number average molecular weight of 100,000 orless as measured by gel permeation chromatography (GPC) calibrated witha poly(methyl methacrylate) (PMMA) standard (as used herein, unlessotherwise specified, all number average molecular weights (M_(n)) referto molecular weight measured in such manner). The copolymeric mitigantis polymerized from at least two monomeric components. The firstmonomeric component is selected from one or more α,β-ethylenicallyunsaturated monomers containing at least one carboxylic acid group. Thisacid group can be derived from monoacids or diacids, anhydrides ofdicarboxylic acids, monoesters of diacids, and salts thereof. The secondmonomeric component is hydrophobically modified (relative to the firstmonomeric component) and is selected from one or more α,β-ethylenicallyunsaturated non-acid monomers containing a C₁ to C₉ alkyl group,including linear and branched C₁ to C₉ alkyl esters of (meth)acrylicacid, vinyl esters of linear and branched C₁ to C₁₀ carboxylic acids,and mixtures thereof. In one aspect of the invention the secondmonomeric component is represented by the formula:

CH₂═CRX

wherein R is hydrogen or methyl; X is —C(O)OR¹ or —OC(O)R²; R¹ is linearor branched C₁ to C₉ alkyl; and R² is hydrogen or linear or branched C₁to C₉ alkyl. In another aspect of the invention R¹ and R² is linear orbranched C₁ to C₈ alkyl and in a further aspect R¹ and R² are linear orbranched C₂ to C₅ alkyl.

Exemplary first monomeric components include (meth)acrylic acid,itaconic acid, citraconic acid, maleic acid, fumaric acid, crotonicacid, aconitic acid, and mixtures thereof. Exemplary second monomericcomponents include ethyl (meth)acrylate, butyl (meth)acrylate,2-ethylhexyl (meth)acrylate, vinyl formate, vinyl acetate, 1-methylvinylacetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinylpivalate, vinyl neodecanoate, and mixtures thereof. As used herein, theterm “(meth)acrylic” acid and “(meth)acrylate” are meant to include thecorresponding methyl derivatives of acrylic acid and the correspondingalkyl acrylate For example, “(meth)acrylic” acid refers to acrylic acidand/or methacrylic acid and “(meth)acrylate” refers to alkyl acrylateand/or alkyl methacrylate.

The non-crosslinked, linear acrylic copolymer mitigants of the inventioncan be synthesized via free radical polymerization techniques known inthe art. In one aspect of the invention, the amount of the firstmonomeric component to the second monomeric component utilized rangesfrom about 20:80 wt. % to about 50:50 wt. %, based on the total weightof all of the monomers in the polymerization medium. In another aspectthe weight ratio of the first monomeric component to the secondmonomeric component is about 35:65 wt. %, and in a further aspect theweight ratio of first monomeric component to second monomeric componentis about 25:75 wt. %, all based on the total weight of all monomers inthe polymerization medium.

In another aspect emulsion polymerization techniques can be used tosynthesize the non-crosslinked, linear acrylic copolymer mitigants ofthe invention. In a typical emulsion polymerization, a mixture of thedisclosed monomers is added with mixing agitation to a solution ofemulsifying surfactant, such as, for example, an anionic surfactant(e.g., fatty alcohol sulfates or alkyl sulfonates), in a suitable amountof water, in a suitable reactor, to prepare a monomer emulsion. Theemulsion is deoxygenated by any convenient method, such as by spargingwith nitrogen, and then a polymerization reaction is initiated by addinga polymerization catalyst (initiator) such as sodium persulfate, or anyother suitable addition polymerization catalyst, as is well known in theemulsion polymerization art. The polymerization medium is agitated untilthe polymerization is complete, typically for a time in the range ofabout 4 to about 16 hours. The monomer emulsion can be heated to atemperature in the range of about 70 to about 95° C. prior to additionof the initiator, if desired. Unreacted monomer can be eliminated byaddition of more catalyst, as is well known in the emulsionpolymerization art. The resulting polymer emulsion product can then bedischarged from the reactor and packaged for storage or use. Optionally,the pH or other physical and chemical characteristics of the emulsioncan be adjusted prior to discharge from the reactor. Typically, theproduct emulsion has a total solids content in the range of about 10 toabout 50 wt. %. Typically, the total polymer content (polymer solids) ofthe product emulsion is in the range of about 15 to about 45 wt. %,generally not more than about 35 wt. %.

In one aspect, the number average molecular weight (M_(n)) of the linearcopolymeric mitigants of the present invention as measured by gelpermeation chromatography (GPC) calibrated with a poly(methylmethacrylate) (PMMA) standard is 100,000 or less. In another aspect ofthe invention, the molecular weight ranges between about 5,000 and about80,000 M_(n), in a further aspect between about 10,000 and 50,000 M_(n),and in a still further aspect between about 15,000 and 40,000 M_(n).

In one aspect of the invention, the linear copolymeric mitigants have aviscosity of 500 mpa·s or less (Brookfield RVT, 20 rpm, spindle no. 1)at a 5 wt. % polymer solids concentration in deionized water andneutralized to pH 7 with an 18 wt. % NaOH solution. The viscosity canrange from about 1 to about 500 mPa·s in another aspect, from about 10to about 250 mPa·s in a further aspect, and from about 15 to about 150mPa·s in a still further aspect.

Any of a variety of anionic surfactants may be combined with a polymericmaterial of the present invention to form a reduced irritationcomposition according to preferred embodiments of the present methods.According to certain embodiments, suitable anionic surfactants includethose selected from the following classes of surfactants: alkylsulfates, alkyl ether sulfates, alkyl monoglyceryl ether sulfates, alkylsulfonates, alkylaryl sulfonates, alkyl sulfosuccinates, alkyl ethersulfosuccinates, alkyl sulfosuccinamates, alkyl amidosulfosuccinates,alkyl carboxylates, alkyl amidoethercarboxylates, alkyl succinates,fatty acyl sarcosinates, fatty acyl amino acids, fatty acyl taurates,fatty alkyl sulfoacetates, alkyl phosphates, and mixtures of two or morethereof. Examples of certain preferred anionic surfactants include:

alkyl sulfates of the formula

R′—CH₂OSO₃X′;

alkyl ether sulfates of the formula

R′(OCH₂CH₂)_(v)OSO₃X′;

alkyl monoglyceryl ether sulfates of the formula

alkyl monoglyceride sulfates of the formula

alkyl monoglyceride sulfonates of the formula

alkyl sulfonates of the formula

R′—SO₃X′;

alkylaryl sulfonates of the formula

alkyl sulfosuccinates of the formula:

alkyl ether sulfosuccinates of the formula:

alkyl sulfosuccinamates of the formula:

alkyl amidosulfosuccinates of the formula

alkyl carboxylates of the formula:

R′ (OCH₂CH₂)_(W)—OCH₂CO₂X′;

alkyl amidoethercarboxylates of the formula:

alkyl succinates of the formula:

fatty acyl sarcosinates of the formula:

fatty acyl amino acids of the formula:

fatty acyl taurates of the formula:

fatty alkyl sulfoacetates of the formula:

alkyl phosphates of the formula:

wherein

-   -   R′ is an alkyl group having from about 7 to about 22, and        preferably fom about 7 to about 16 carbon atoms,    -   R′₁ is an alkyl group having from about 1 to about 18, and        preferably from about 8 to about 14 carbon atoms,    -   R′₂ is a substituent of a natural or synthetic I-amino acid,    -   X′ is selected from the group consisting of alkali metal ions,        alkaline earth metal ions, ammonium ions, and ammonium ions        substituted with from about 1 to about 3 substituents, each of        the substituents may be the same or different and are selected        from the group consisting of alkyl groups having from 1 to 4        carbon atoms and hydroxyalkyl groups having from about 2 to        about 4 carbon atoms and    -   v is an integer from 1 to 6;    -   w is an integer from 0 to 20;        and mixtures thereof.

According to certain embodiments, the anionic surfactant of the presentinvention preferably comprises one or more alkyl ether sulfates, ormixtures thereof. In certain more preferred embodiments, the anionicsurfactant of the present invention comprises sodium trideceth sulfate.Sodium trideceth sulfate is the sodium salt of sulfated ethoxylatedtridecyl alcohol that conforms generally to the following formula,C₁₃H₂₇(OCH₂CH₂)_(n)OSO₃Na, where n has a value between 1 and 4, and iscommercially available from Stepan Company of Northfield, Ill. under thetradename, “Cedapal TD-403M.”

As used herein, the term “amphoteric” shall mean: 1) molecules thatcontain both acidic and basic sites such as, for example, an amino acidcontaining both amino (basic) and acid (e.g., carboxylic acid, acidic)functional groups; or 2) zwitterionic molecules which possess bothpositive and negative charges within the same molecule. The charges ofthe latter may be either dependent on or independent of the pH of thecomposition. Examples of zwitterionic materials include, but are notlimited to, alkyl betaines and amidoalkyl betaines. The amphotericsurfactants are disclosed herein without a counter ion. One skilled inthe art would readily recognize that under the pH conditions of thecompositions of the present invention, the amphoteric surfactants areeither electrically neutral by virtue of having balancing positive andnegative charges, or they have counter ions such as alkali metal,alkaline earth, or ammonium counter ions.

Examples of amphoteric surfactants suitable for use in the presentinvention include, but are not limited to, amphocarboxylates such asalkylamphoacetates (mono or di); alkyl betaines; amidoalkyl betaines;amidoalkyl sultaines; amphophosphates; phosphorylated imidazolines suchas phosphobetaines and pyrophosphobetaines; carboxyalkyl alkylpolyamines; alkylimino-dipropionates; alkylamphoglycinates (mono or di);alkylamphoproprionates (mono or di),); N-alkyl β-aminoproprionic acids;alkylpolyamino carboxylates; and mixtures thereof.

Examples of suitable amphocarboxylate compounds include those of theformula:

A-CONH(CH₂)_(x)N⁺R₅R₆R₇

-   -   wherein    -   A is an alkyl or alkenyl group having from about 7 to about 21,        e.g. from about 10 to about 16 carbon atoms;    -   x is an integer of from about 2 to about 6;    -   R₅ is hydrogen or a carboxyalkyl group containing from about 2        to about 3 carbon atoms;    -   R₆ is a hydroxyalkyl group containing from about 2 to about 3        carbon atoms or is a group of the formula:

R₈—O—(CH₂)_(n)CO₂ ⁻

-   -   -   wherein        -   R₈ is an alkylene group having from about 2 to about 3            carbon atoms and n is 1 or 2; and

    -   R₇ is a carboxyalkyl group containing from about 2 to about 3        carbon atoms;

Examples of suitable alkyl betaines include those compounds of theformula:

B—N⁺R₉R₁₀(CH₂)_(p)CO₂ ⁻

-   -   wherein        -   B is an alkyl or alkenyl group having from about 8 to about            22, e.g., from about 8 to about 16 carbon atoms;        -   R₉ and R₁₀ are each independently an alkyl or hydroxyalkyl            group having from about 1 to about 4 carbon atoms; and        -   p is 1 or 2.

A preferred betaine for use in the present invention is lauryl betaine,available commercially from Albright & Wilson, Ltd. of West Midlands,United Kingdom as “Empigen BB/J.”

Examples of suitable amidoalkyl betaines include those compounds of theformula:

D-CO—NH(CH₂)_(q)—N⁺R₁₁R₁₂(CH₂)_(m)CO₂ ⁻

-   -   wherein        -   D is an alkyl or alkenyl group having from about 7 to about            21, e.g. from about 7 to about 15 carbon atoms;        -   R₁₁ and R₁₂ are each independently an alkyl or Hydroxyalkyl            group having from about 1 to about 4 carbon atoms;        -   q is an integer from about 2 to about 6; and m is 1 or 2.

One amidoalkyl betaine is cocamidopropyl betaine, available commerciallyfrom Goldschmidt Chemical Corporation of Hopewell, Va. under thetradename, “Tegobetaine L7.”

Examples of suitable amidoalkyl sultaines include those compounds of theformula

-   -   wherein        -   E is an alkyl or alkenyl group having from about 7 to about            21, e.g. from about 7 to about 15 carbon atoms;        -   R₁₄ and R₁₅ are each independently an alkyl, or hydroxyalkyl            group having from about 1 to about 4 carbon atoms;        -   r is an integer from about 2 to about 6; and        -   R₁₃ is an alkylene or hydroxyalkylene group having from            about 2 to about 3 carbon atoms;

In one embodiment, the amidoalkyl sultaine is cocamidopropylhydroxysultaine, available commercially from Rhone-Poulenc Inc. ofCranbury, N.J. under the tradename, “Mirataine CBS.”

Examples of suitable amphophosphate compounds include those of theformula:

-   -   wherein        -   G is an alkyl or alkenyl group having about 7 to about 21,            e.g. from about 7 to about 15 carbon atoms;            -   s is an integer from about 2 to about 6;            -   R₁₆ is hydrogen or a carboxyalkyl group containing from                about 2 to about 3 carbon atoms;            -   R₁₇ is a hydroxyalkyl group containing from about 2 to                about 3 carbon atoms or a group of the formula:

R₁₉—O—(CH₂)_(t)—CO₂ ⁻

-   -   -   -   -   wherein                -    R₁₉ is an alkylene or hydroxyalkylene group having                    from about 2 to about 3 carbon atoms and                -    t is 1 or 2; and

        -   R₁₈ is an alkylene or hydroxyalkylene group having from            about 2 to about 3 carbon atoms.

In one embodiment, the amphophosphate compounds are sodium lauroamphoPG-acetate phosphate, available commercially from Mona Industries ofPaterson, N.J. under the tradename, “Monateric 1023,” and thosedisclosed in U.S. Pat. No. 4,380,637, which is incorporated herein byreference.

Examples of suitable phosphobetaines include those compounds of theformula:

wherein E, r, R₁, R₂ and R₃, are as defined above. In one embodiment,the phosphobetaine compounds are those disclosed in U.S. Pat. Nos.4,215,064, 4,617,414, and 4,233,192, which are all incorporated hereinby reference.

Examples of suitable pyrophosphobetaines include those compounds of theformula:

wherein E, r, R₁, R₂ and R₃, are as defined above. In one embodiment,the pyrophosphobetaine compounds are those disclosed in U.S. Pat. Nos.4,382,036, 4,372,869, and 4,617,414, which are all incorporated hereinby reference.

Examples of suitable carboxyalkyl alkylpolyamines include those of theformula:

-   -   wherein        -   I is an alkyl or alkenyl group containing from about 8 to            about 22, e.g. from about 8 to about 16 carbon atoms;        -   R₂₂ is a carboxyalkyl group having from about 2 to about 3            carbon atoms;

R₂₁ is an alkylene group having from about 2 to about 3 carbon atoms and

-   -   -   u is an integer from about 1 to about 4.

Any suitable amounts of polymeric material and surfactants may be usedin accord with the present invention. In certain preferred embodiments,the present composition comprise from greater than zero to about 6weight percent of polymeric material (based on active amount ofpolymeric material in the total weight of composition). In certain morepreferred embodiments, the compositions comprise from about 0.1 to about4.5 weight percent of polymeric material, more preferably from about 0.3to about 3.5 weight percent of polymeric material, and even morepreferably from about 0.5 to about 2.5 weight percent of polymericmaterial. In certain preferred embodiments, the present compositioncomprise from greater than zero to about 30 weight percent ofanionic/amphoteric surfactant (based on total active amount of anionicand/or amphoteric surfactant(s) in the total weight of composition). Incertain more preferred embodiments, the compositions comprise from about1 to about 25 weight percent of anionic/amphoteric surfactant, morepreferably from about 5 to about 25 weight percent of anionic/amphotericsurfactant, and even more preferably from about 9 to about 20 weightpercent of anionic/amphoteric surfactant.

The polymeric material and anionic/amphoteric surfactant may be combinedaccording to the present invention via any conventional methods ofcombining two or more fluids. For example, one or more compositionscomprising, consisting essentially of, or consisting of at least onepolymeric material and one or more compositions comprising, consistingessentially of, or consisting of at least one anionic and/or amphotericsurfactant may be combined by pouring, mixing, adding dropwise,pipetting, pumping, and the like, one of the compositions comprisingpolymeric material or surfactant into or with the other in any orderusing any conventional equipment such as a mechanically stirredpropeller, paddle, and the like. According to certain embodiments, thecombining step comprises combining a composition comprising anionicand/or amphoteric surfactant into or with a composition comprisingpolymeric material. According to certain other embodiments, thecombining step comprises combining a composition comprising polymericmaterial into or with a composition comprising anionic and/or amphotericsurfactant.

The reduced irritation compositions produced, as well as any of thecompositions comprising polymeric material or anionic and/or amphotericsurfactant that are combined in the combining step according to thepresent methods may further comprise any of a variety of othercomponents nonexclusively including one or more nonionic and/or cationicsurfactants, pearlescent or opacifying agents, thickening agents,secondary conditioners, humectants, chelating agents, and additiveswhich enhance the appearance, feel and fragrance of the compositions,such as colorants, fragrances, preservatives, pH adjusting agents, andthe like.

Any of a variety of nonionic surfactants are suitable for use in thepresent invention. Examples of suitable nonionic surfactants include,but are not limited to, fatty alcohol acid or amide ethoxylates,monoglyceride ethoxylates, sorbitan ester ethoxylates alkylpolyglycosides, mixtures thereof, and the like. Certain preferrednonionic surfactants include polyoxyethylene derivatives of polyolesters, wherein the polyoxyethylene derivative of polyol ester (1) isderived from (a) a fatty acid containing from about 8 to about 22, andpreferably from about 10 to about 14 carbon atoms, and (b) a polyolselected from sorbitol, sorbitan, glucose, α-methyl glucoside,polyglucose having an average of about 1 to about 3 glucose residues permolecule, glycerine, pentaerythritol and mixtures thereof, (2) containsan average of from about 10 to about 120, and preferably about 20 toabout 80 oxyethylene units; and (3) has an average of about 1 to about 3fatty acid residues per mole of polyoxyethylene derivative of polyolester. Examples of such preferred polyoxyethylene derivatives of polyolesters include, but are not limited to PEG-80 sorbitan laurate andPolysorbate 20. PEG-80 sorbitan laurate, which is a sorbitan monoesterof lauric acid ethoxylated with an average of about 80 moles of ethyleneoxide, is available commercially from ICI Surfactants of Wilmington,Del. under the tradename, “Atlas G-4280.” Polysorbate 20, which is thelaurate monoester of a mixture of sorbitol and sorbitol anhydridescondensed with approximately 20 moles of ethylene oxide, is availablecommercially from ICI Surfactants of Wilmington, Del. under thetradename “Tween 20.”

Another class of suitable nonionic surfactants includes long chain alkylglucosides or polyglucosides, which are the condensation products of (a)a long chain alcohol containing from about 6 to about 22, and preferablyfrom about 8 to about 14 carbon atoms, with (b) glucose or aglucose-containing polymer. Preferred alkyl gluocosides comprise fromabout 1 to about 6 glucose residues per molecule of alkyl glucoside. Apreferred glucoside is decyl glucoside, which is the condensationproduct of decyl alcohol with a glucose polymer and is availablecommercially from Henkel Corporation of Hoboken, N.J. under thetradename, “Plantaren 2000.”

Classes of cationic surfactants that are suitable for use in thisinvention include alkyl quaternaries (mono, di, or tri), benzylquaternaries, ester quaternaries, ethoxylated quaternaries, alkylamines, and mixtures thereof, wherein the alkyl group has from about 6carbon atoms to about 30 carbon atoms, with about 8 to about 22 carbonatoms being preferred.

Any of a variety of commercially available secondary conditioners, suchas volatile silicones, which impart additional attributes, such as glossto the hair are suitable for use in this invention. In one embodiment,the volatile silicone conditioning agent has an atmospheric pressureboiling point less than about 220° C. The volatile silicone conditionermay be present in an amount of from about 0 percent to about 3 percent,e.g. from about 0.25 percent to about 2.5 percent or from about 0.5percent to about 1.0 percent, based on the overall weight of thecomposition. Examples of suitable volatile silicones nonexclusivelyinclude polydimethylsiloxane, polydimethylcyclosiloxane,hexamethyldisiloxane, cyclomethicone fluids such aspolydimethylcyclosiloxane available commercially from Dow CorningCorporation of Midland, Mich. under the tradename, “DC-345” and mixturesthereof, and preferably include cyclomethicone fluids.

Any of a variety of commercially available humectants, which are capableof providing moisturization and conditioning properties to the personalcleansing composition, are suitable for use in the present invention.The humectant may be present in an amount of from about 0 percent toabout 10 percent, e.g. from about 0.5 percent to about 5 percent or fromabout 0.5 percent to about 3 percent, based on the overall weight of thecomposition. Examples of suitable humectants nonexclusively include: 1)water soluble liquid polyols selected from the group comprisingglycerine, propylene glycol, hexylene glycol, butylene glycol,dipropylene glycol, and mixtures thereof; 2) polyalkylene glycol of theformula: HO—(R′O)_(b)—H, wherein R″ is an alkylene group having fromabout 2 to about 3 carbon atoms and b is an integer of from about 2 toabout 10; 3) polyethylene glycol ether of methyl glucose of formulaCH₃—C₆H₁₀O₅—(OCH₂CH₂)_(c)—OH, wherein c is an integer from about 5 toabout 25; 4) urea; and 5) mixtures thereof, with glycerine being thepreferred humectant.

Examples of suitable chelating agents include those which are capable ofprotecting and preserving the compositions of this invention.Preferably, the chelating agent is ethylenediamine tetracetic acid(“EDTA”), and more preferably is tetrasodium EDTA, availablecommercially from Dow Chemical Company of Midland, Mich. under thetradename, “Versene 100XL” and is present in an amount, based upon thetotal weight of the composition, from about 0 to about 0.5 percent orfrom about 0.05 percent to about 0.25 percent.

Suitable preservatives include Quaternium-15, available commercially as“Dowicil 200” from the Dow Chemical Corporation of Midland, Mich., andare present in the composition in an amount, based upon the total weightof the composition, from about 0 to about 0.2 percent or from about 0.05percent to about 0.10 percent.

The methods of the present invention may further comprise any of avariety of steps for mixing or introducing one or more of the optionalcomponents described hereinabove with or into a composition comprising apolymeric material and/or an anionic and/or amphoteric surfactant eitherbefore, after, or simultaneously with the combining step describedabove. While in certain embodiments, the order of mixing is notcritical, it is preferable, in other embodiments, to pre-blend certaincomponents, such as the fragrance and the nonionic surfactant beforeadding such components into a composition comprising a polymericmaterial and/or an anionic surfactant.

In certain embodiments, the reduced irritation compositions produced viathe present invention are preferably used as or in personal carecompositions/products. As used herein, the term “personal care” relatesto compositions/products for use on or in the body for cosmetic/healthcare purposes and the like. For example, personal care products include,but are not limited to, products for use in skin care, infant care, oralcare, wound care, sanitary protection, cleansing, women's health,sleep-related products, make-up, cosmetic dermatology, eye care, earcare, nail care, depilatories, hair care, sun protection, anti-aging,anti-acne, and the like. Examples of types of such products may include,but are not limited to, shampoos, washes, baths, gels, lotions, creams,wipes and other applicators, napkins, liners, tampons, bandages,toothbrushes, floss, dental strips, microdermabrasion devices, and thelike. As discussed above, applicants have discovered unexpectedly thatthe instant methods allow for the formulation of such personal careproducts having reduced irritation to the skin and/or eyes andoptionally other combinations of desirable aesthetics.

According to certain other preferred embodiments, the present inventionprovides methods for treating and/or cleansing a portion of the body,including the skin, hair, teeth, vagina, and the like, preferably theskin or hair, with reduced irritation thereto comprising the step ofcontacting the body of a mammal with a reduced irritation composition ofthe present invention.

Any conventional means for contacting the body, preferably mammalianskin and/or hair, can be used according to the present invention. Incertain preferred embodiments, the contacting step comprises applying areduced irritation composition of the present invention to human skinand/or human hair.

The cleansing methods of the present invention may further comprise anyof a variety of additional, optional steps associated conventionallywith cleansing hair and skin including, for example, lathering, rinsingsteps, and the like.

EXAMPLES

The following examples are illustrative of certain embodiments of thepresent invention and are not intended to be limiting in any manner.

The following Trans-Epithelial Permeability (“TEP”), Tensiometry tests,M_(n) and C₉₀ Measurements are used in the instant methods and in thefollowing Examples.

Trans-Epithelial Permeability Test (“TEP Test”):

Irritation to the eyes and/or skin expected for a given formulation ismeasured in accordance with the Invittox Protocol Number 86, the“Trans-epithelial Permeability (TEP) Assay” as set forth in InvittoxProtocol Number 86 (May 1994), incorporated herein by reference. Ingeneral, the ocular and/or skin irritation potential of a product can beevaluated by determining its effect on the permeability of a cell layer,as assessed by the leakage of fluorescein through the layer. Monolayersof Madin-Darby canine kidney (MDCK) cells are grown to confluence onmicroporous inserts in a 24-well plate containing medium or assay bufferin the lower wells. The irritation potential of a product is evaluatedby measuring the damage to the permeability barrier in the cellmonolayer following a 15 minute exposure to dilutions of the product.Barrier damage is assessed by the amount of sodium fluorescein that hasleaked through to the lower well after 30 minutes, as determinedspectrophotometrically. The fluorescein leakage is plotted against theconcentration of test material to determine the EC₅₀ (the concentrationof test material that causes 50% of maximum dye leakage, i.e., 50%damage to the permeability barrier). Higher scores are indicative ofmilder formulas.

Exposure of a layer of MDCK cells grown on a microporous membrane to atest sample is a model for the first event that occurs when an irritantcomes in contact with the eye. In vivo, the outermost layers of thecorneal epithelium form a selectively permeable barrier due to thepresence of tight junctions between cells. On exposure to an irritant,the tight junctions separate, thereby removing the permeability barrier.Fluid is imbibed to the underlying layers of epithelium and to thestroma, causing the collagen lamellae to separate, resulting in opacity.The TEP assay measures the effect of an irritant on the breakdown oftight junctions between cells in a layer of MDCK cells grown on amicroporous insert. Damage is evaluated spectrophotometrically, bymeasuring the amount of marker dye (sodium fluorescein) that leaksthrough the cell layer and microporous membrane to the lower well.

Tensiometry Titration Test:

A well-known method to measure the surface tension of surfactantsolutions is the Wilhelmy plate method (Holmberg, K.; Jonsson, B.;Kronberg, B.; Lindman, B. Surfactants and Polymers in Aqueous Solution,Wiley & Sons, p. 347). In the method, a plate is submerged into a liquidand the downward force exerted by of the liquid on the plate ismeasured. The surface tension of the liquid can then be determined basedon the force on the plate and the dimensions of the plate. It is alsowell known that by measuring the surface tension over a range ofconcentrations the critical micelle concentration (CMC) can then bedetermined.

There are commercially available Wilhelmy plate method instruments. Inthe following examples, a Kruss K12 Tensiomter (Kruss USA, Mathews,N.C.) with a platinum Wilhelmy plate used to determine the surfacetension of each sample over a range of concentrations. The test can berun either forward or reverse. In either case, a sample vessel containssome initial solution in which the Wilhelmy plate measures the surfacetension. Then a second solution is dosed into the sample vessel,stirred, and then probed again with the Wilhelmy plate. The solutioninitially in the sample vessel before the titration begins, into whichthe second solution is dosed, will be referred to hereinafter as theinitial solution, and the solution that is dosed into the sample vesselduring the titration will be referred to hereinafter as the dosingsolution, in accordance with the convention used by Kruss USA.

In the forward titration, the concentration of the initial solution islower than the concentration of the dosing solution. During forwardtitration tests, the initial solution was HLPC grade water (FischerScientific, N.J.), with no surfactant. The dosing solution was asolution of surfactant to be associated with the polymer and HLPC gradewater (Fischer Scientific, N.J.) with a concentration of 5750 mg/L ofsurfactant. A large stock solution, 4 L, of the dosing surfactantsolution was prepared before hand; the surfactant was added to HLPCgrade water (Fischer Scientific, N.J.) to a concentration of 5750 mg/L.

At the beginning of the forward titration, 30 ml of initial solution wasadded to the sample vessel. The surface tension of this initial solutionwas measured, and then a volume of the dosing solution was added to thesample vessel. The solution was stirred for at least 5 minutes, beforethe next surface tension measures was taken. At least forty volumes ofdosing solution are added and the surface tension measured afteraddition. All titrations were run from 0 mg/L to at least 3500 mg/L ofthe surfactant. A test run according to this procedure is here afterreferred to as a Forward Titration Tensiomtry Test.

Alternatively in the reverse titration, the concentration of the initialsolution is higher than the concentration of the dosing solution. Duringthe reverse titration tests, the dosing solution is HLPC grade water(Fischer Scientific, N.J.), with no surfactant, 0 mg/L. The fullconcentration formulas are diluted with HLPC grade water (FischerScientific, N.J.) to a dilution of approximately 5% wt. This 5% dilutedsolution is then added to the sample vessel and is the initial solution.The surface tension of this initial solution is measured, and then a 30ml volume of the dosing solution is added to the sample vessel. Thesolution was stirred for at least 5 minutes, before the next surfacetension measures is taken. This dosing, stirring, and then measuring wasrepeated until the dilution reached at least 0.0008%. A Test runaccording to this procedure is here after referred to as a ReverseTitration Tensiomtry Test.

From the raw tensiomtry data, the CMC was determined for each sample inthe following manner. First, the equation for a horizontal line wasfitted to the portion of the data at high concentrations, i.e.concentrations above the nadir of the graph and well into the regionwhere the surface tension is essentially constant, as shown, forexample, in FIG. 3 as line 31. Then, the equation for a straight line isfit to the data at lower concentrations having a surface tension abovethe horizontal line derived previously, as shown, for example, in FIG. 3as line 32. The intersection of these two lines/equations 33 was thendefined as the CMC for that sample.

C₉₀ Measurements

The C₉ o attributed to a polymer for associating a surfactant thereto iscalculated as follows. Eight compositions comprising the polymer in HPLCgrade water at concentrations (in mg/L) of: 0, 50, 100, 175, 250, 375,500 and 750 are prepared. The CMC associated with each composition witha particular surfactant are calculated via the Forward TensiometryTitration test. The Delta CMC for each of the compositions comprisingpolymer are then calculated using such data. Based on such Delta CMCdata and/or graphical representation of the Delta CMCs as a function ofpolymer concentration fit with an appropriate curve, the lowestconcentration polymer composition which exhibits a Delta CMC value thatis 90% of the Delta CMC value of the polymer composition having aconcentration of 750 mg/L is determined, and such concentration valuerepresents the C₉₀ value for such polymer and surfactant combination.Reference is made, for example, to the procedure in Example 1.

Molecular Weight Determination

The number average (M_(n)) of the polymer samples are determined via theGPC method using a PL-220 high temperature GPC instrument manufacturedby Polymer Laboratories. The instrument is integrated with a Compaq DellOptiPlex GX270 computer with Waters Empower Pro LC/GPC software.Approximately 0.02 g polymer sample is dissolved in 5 ml of dimethylactamide (DMAc), containing 250 ppm BHT and 0.05 molar NaNO₃. The testsample solution is gently shaken for about two hours and filtered with a0.45 μm PTFE disposable disc filter. The chromatographic conditions are:

-   Mobile phase: DMAc, with 250 ppm BHT and 0.05 m NaNO₃, 70° C., 1.0    ml min.-   Sample size: 100 μl-   Column set: PLgel (Guard+2×Mixed-B), all 10 μm, in series-   Detector: Refractive Index Detector-   Calibration standard: PMMA

Example 1

The following example illustrates the efficiency of certain polymers ofthe present invention to associate surfactant thereto and reduceirritation as compared to higher molecular weight polymeric materials.

Compositions (E1-E5) comprising a non-crosslinked, linear acryliccopolymer derived from methacrylic acid and ethyl acrylate, wherein themethacrylic acid:ethyl acrylate ratio is about 25:75% %, based on thetotal weight of all of the monomers in the polymerization medium andhaving a M_(n) of from about 15,000 to about 40,000 from Noveon, Inc.(“Ex. 968”) in water, and comparable compositions comprising no polymer(C1), higher molecular weight polymers (C2-C8), and comparable lowmolecular weight polymer (C9-C15) were prepared as described below. TheCMCs, Delta CMCs, and Delta CMC/750 for each composition with surfactantsodium trideceth sulfate (TDES) were calculated using the ForwardTitration Tensiomtry Test as described herein and the results reportedin Table 2.

TABLE 1* Trade name INCI Name E1 E2 E3 E4 E5 Ex. 968 0.010 0.025 0.0350.050 0.075 Sodium Hydroxide Sodium — — — — — solution (20%) HydroxideDI Water DI Water Qs Qs Qs Qs Qs Trade name INCI Name C1 C2 C3 C4 C5 C6C7 C8 Carbopol AQUA Acrylates — 0.005 0.010 0.015 0.025 0.0375 0.0500.075 SF1 (30%) Copolymer Sodium Sodium As As As As As As As AsHydroxide Hydroxide needed needed needed needed needed needed neededneeded solution (20%) DI Water DI Water Qs Qs Qs Qs Qs Qs Qs qs Tradename INCI Name C9 C10 C11 C12 C13 C14 C15 Inutec SP-1 Inulin Lauryl0.005 0.010 0.0175 0.025 0.0375 0.050 0.075 Carbamate Sodium Sodium — —— — — — — Hydroxide Hydroxide (20%) DI Water DI Water Qs Qs Qs Qs Qs Qsqs *expressed in % W/W

The compositions of Table 1 were prepared as follows: HPLC grade water(50.0 parts) was added to a beaker. The polymer, if any, was added tothe water with mixing. For the solutions containing Carbopol Aqua SF-1,the pH of each resulting solution was then adjusted with a 20% SodiumHydroxide solution (as needed) until a final pH of about 7.0 wasobtained. The remainder of the water was then added thereto.

The compositions of Table 1 were tested for Critical MicelleConcentration (CMC) values using the Forward Titration Tensiomtry Test.The Delta CMCs for each composition were calculated based on the CMC forcomparable composition C1 and such values were plotted as a function ofpolymer concentration in FIG. 1 as an illustration of the efficiency ofthe polymers to associate surfactant thereto (and reduce irritation).

TABLE 2 CMC Δ CMC Ex. 968 TDES TDES Examples (mg/L) (mg/L) (mg/L)Efficiency Δ CMC/750 % 0 136 na na na E1 100 269 133 1.3 35 E2 250 362226 0.9 59 E3 350 386 250 0.7 66 E4 500 454 318 0.6 83 E5 750 517 3810.5 100 CMC Δ CMC Aqua SF-1 TDES TDES Examples (mg/L) (mg/L) (mg/L)Efficiency Δ CMC/750 % C1 0 136 na na na C2 50 213 77 1.5 26 C3 100 291155 1.6 52 C4 150 328 192 1.3 64 C5 250 410 274 1.1 92 C6 375 468 3320.9 111 C7 500 431 295 0.6 99 C8 750 434 298 0.4 100 CMC Δ CMC Com-Inutec SP-1 TDES TDES Δ position (mg/L) (mg/L) (mg/L) Efficiency CMC/750% C1 0 136 na na na C9 50 182 46 0.9 7 C10 100 258 122 1.2 18 C11 175370 234 1.3 34 C12 250 452 316 1.3 46 C13 375 595 459 1.2 66 C14 500 777641 1.3 92 C15 750 830 694 0.9 100

Also shown in Table 2 for each of the compositions is the Efficiency,which is defined herein as the ratio of the Delta CMC (mg/L) to thepolymer concentration. The Efficiency is a measure of how muchsurfactant the polymer associates at a given concentration.

To better assess the differences between the polymers in efficiency as afunction of polymer concentration also shown in Table 2 is ΔCMC/750,which is defined herein as the ratio of the ΔCMC at a particularconcentration to the ΔCMC of a composition having a polymerconcentration of 750 mg/L (times 100 to get a % value). The ΔCMC/750provides a metric of the extent to which the polymer tends to loseefficiency as concentration of the polymer is increased. For instanceAqua SF-1 reaches a ΔCMC/750 of 92% at a polymer concentration of onlyabout 250 ml/L, while Inutec SP-1 does not reach a ΔCMC/750 of 92% untila polymer concentration of about 500 mg/L. This suggests that while apolymer concentration of Aqua SF-1 above 250 mg/L tends to providerelatively little additional TDES association, Inutec SP-1 is capable ofassociating relatively significant amounts of additional surfactant atconcentrations greater than 500 mg/L. The “C₉₀ value” of a polymer andsurfactant combination is the lowest polymer concentration at which theΔCMC/750 of compositions comprising the polymer and surfactant, asmeasured via the Forward Titration Tensiomtry Test as describedhereinabove, is equal to 90%. As shown above, the C₉₀ value associatedwith the comparable SF-1 polymer and TDES is less than about 250 mg/L,while the Inutec SP-1 polymer and TDES is greater than about 250 mg/L(about 500 mg/L) and the C₉₀ value associated with Ex. 968 and TDES isgreater than about 250 mg/L (and greater than about 500 mg/L).

Example 2

The following example illustrates the efficiency of certain polymers ofthe present invention to associate surfactant thereto and reduceirritation as compared to other low molecular weight polymericmaterials.

The CMCs, Delta CMCs, Efficiency, Delta CMC/750, and C₉₀ forCompositions (E1-5) and comparable compositions comprising a lowmolecular weight octadecene/maleic anhydride copolymer designated“PA-18” with the surfactant cocamidopropyl betaine (CAPB) werecalculated using the Forward Titration Tensiomtry Test as describedbelow and the results reported in Table 3.

The compositions were tested for Critical Micelle Concentration (CMC)values using the Forward Titration Tensiomtry Test. The Delta CMCs foreach composition were calculated based on the CMC for comparablecomposition C1.

TABLE 3 CMC Δ CMC Ex- CAPB CAPB Δ CMC/750 amples (mg/L) (mg/L)Efficiency CAPB % Ex. 968 (mg/L) C1 0 na na Na E1 50 191 174 3.5 6 E2250 920 903 3.6 34 E3 E4 500 1522 1505 3.0 56 E5 750 2698 2681 3.6 100PA-18 (mg/L) C1 0 na na Na C16 50 309 254 5.1 11 C17 250 1225 1128 4.548 C18 350 1611 1481 4.2 63 C19 500 2100 1905 3.8 82 C20 750 2675 23333.1 100

As shown in Table 3, the C₉₀ value associated with the Ex. 968 polymerand CAPB is greater than about 250 mg/L (and greater than 500 mg/L).

Example 3

The following example illustrates the significant clarity associatedwith compositions of certain embodiments of the present invention ascompared to other comparable compositions comprising other low molecularweight polymeric materials and high molecular weight polymericmaterials.

Composition E6 in accord with the present invention and comparativecompositions C21-C23 were prepared and the clarity measured for eachcomposition.

TABLE 4 C21 C22 E6 C23 Trade Name INCI name w/w % w/w % w/w % w/w %Cedepal TD-403 (30%) Sodium trideceth sulfate 9.00 9.00 9.00 9.00Tegobetaine L-7V Cocamidopropyl betaine 9.00 9.00 9.00 9.00 Merquat SPolyquaternium-7 0.14 0.14 0.14 0.14 Versene 100 XL Tetrasodium EDTA0.10 0.10 0.10 0.10 Aqua SF-1 (30%) Acrylates copolymer — 6.00 — —Ex-968 (30%) Acrylates copolymer (low Mw) — — 6.00 Inutec SP-1 InulinLauryl Carbamate — — — 1.8  20% NaOH Sodium hydroxide qs qs qs qsDeionized water Water qs qs qs qs *expressed in % W/W

Each of the compositions of Table 4 was independently prepared asfollows: Water (50.0 parts) was added to a beaker. The followingingredients were then added thereto independently with mixing until eachrespective resulting mixture was homogenous: Ex. 968, Aqua SF-1 orInutec SP-1 (depending on the example), Cedepal TD403MF-D, TegobetaineL7-V, Merquat S, Versene 100XL, and Nipasept. The pH of the resultingsolution was then adjusted with a 20% solution of Citric Acid of Sodiumhydroxide solution until a final pH of about 6.3 to 6.6 was obtained.The remainder of the water was then added thereto.

The clarity of each sample was measured via the Clarity Test, theprocedure for which comprises preparing a 1 cm cell sample of thecomposition to be measured and measuring the % light transmittanceassociated with such sample using a Agilent 8453 UV-VisibleSpectrophotometer with a 1 cm cell at a wavelength of 800 nm. Theresults are shown in Table 5.

TABLE 5 Clarity Example Polymer added (% transmitance) C21 No polymer99.1 ± 0.2 E6 Ex-968 98.8 ± 0.1 C22 Aqua SF-1 88.3 ± 0.2 C23 Inutec SP-137.1 ± 0.9

Example 4

This example further illustrates the clarity associated withcompositions of the present invention as compared to comparablecompositions comprising other low molecular weight polymers and/or highmolecular weight polymers.

The turbidity associated with five commercial cleansing products wasmeasured using the Turbidity test as follows: the turbidity of asurfactant containing composition was determined in NephelometricTurbidity Units (NTU) employing a nephelometric turbidity meter (Mircro100 Turbidimeter, HF Scientific, Inc.) with distilled water (NTU=0) asthe standard. Six dram screw cap vials (70 mm×25 mm) are filled almostto the top with test sample and centrifuged at 100 rpm until all bubblesare removed. Upon centrifugation each sample vial is wiped with tissuepaper to remove any smudges before placement in the turbidity meter. Thesample is placed in the turbidity meter and a reading is taken. Once thereading stabilizes the NTU value is recorded. The vial is givenone-quarter turn and another reading is taken and recorded. This isrepeated until four readings are taken. The lowest of the four readingsis reported as the turbidity value. Compositions having an NTU value ofabout 90 or greater were judged turbid.

The five commercial products were as follows: Johnson's Baby Shampoo(JBS) which contains the ingredients as listed on the label (Water,PEG-80 Sorbitan Laurate, Cocamidopropyl Betaine, Sodium TridecethSulfate, Glycerin, Lauroamphoglycinate, PEG-150 Distearate, SodiumLaureth-13 Carboxylate, Fragrance, Polyquaternium-10, Tetrasodium EDTA,Quaternium-15, Citric Acid, D&C Yellow 10); Johnson's Baby ShampooDetangling (JBS Detangling) which contains the ingredients as listed onthe label (Water, Cocamidopropyl Betaine, PEG-80 Sorbitan Laurate,Sodium Trideceth Sulfate, PEG 150 Distearate, Fragrance,Polyquaternium-10, Tetrasodium EDTA, Quaternium-15, Citric Acid, FD&CRed 40, D&C Yellow 10; Johnson's Baby Shampoo with Natural Lavender (JBSLavender) which contains the ingredients as listed on the label, (Water,PEG-80 Sorbitan Laurate, Cocamidopropyl Betaine, Sodium TridecethSulfate, Glycerin, Disodium Lauroamphodiacetate, PEG 150 Distearate,Sodium Laureth 13 Carboxylate, Fragrance (Lavender & Chamomile),Polyquaternium-10, Tetrasodium EDTA, Quaternium-15, Ext D&C Violet 2);Johnson's Head-to-Toe Body Wash (HTT) which contains the ingredients aslisted on the label (Water/Eau, Cocamidopropyl Betaine, PEG-80 SorbitanLaurate, Sodium Laureth Sulfate, PEG-150 Distearate, Tetrasodium EDTA,Sodium Chloride, Polyquaternium-10, Fragrance, Quatermium-15, CitricAcid); and Johnson's Kids Head-to-Toe Body Wash Berry Breeze (Johnson'sKids) which contains the ingredients as listed on the label (Water,PEG-80 Sorbitan Laurate, Cocamidopropyl Betaine, Sodium TridecethSulfate, Glycerin, PEG 150 Distearate, Disodium Lauroamphodiacetate,Sodium Laureth 13 Carboxylate, Fragrance, Polyquaternium-10, TetrasodiumEDTA, Quaternium-15, FD&C Red 40, D&C Red 33).

Six gram samples of Ex. 968 and SF-1 were independently added to 94 gramsamples of each of the five commercial products and the turbidityassociated with each new composition measured via the Turbidity test.The results of all such measurements is shown in Table 6.

TABLE 6 Turbidity Base Polymer added (NTU) JBS No polymer 2.2 JBS Ex-9685.6 JBS Aqua SF-1 133 JBS Detangling No polymer 1.0 JBS DetanglingEx-968 4.0 JBS Detangling Aqua SF-1 27 JBS Lavender No polymer 2.0 JBSLavender Ex-968 2.0 JBS Lavender Aqua SF-1 355 Johnson's Kids No polymer0.0 Johnson's Kids Ex-968 4.0 Johnson's Kids Aqua SF-1 550 HTT Nopolymer 0.0 HTT Ex-968 0.0 HTT Aqua SF-1 520

As seen in Table 5, example C21 (without any polymer) and Example E6(with Ex. 968) had excellent clarity with 99.1% and 98.8 transmittance,respectively. While Examples C22 (with Aqua SF-1) and C23 (with InutecSP-1) were observed to be significantly less clear. These results arefurther confirmed as shown in Table 6. The polymer Ex. 968 has excellentclarity (low turbidity) when added to a variety of clear bases(comparable to the clear formula without any additional polymer), whileAqua SF-1 has significantly poorer clarity (higher turbidity). While allthree polymers (Aqua SF-1, Inutec SP-1 and Ex. 968) tended to provideirritation mitigation, only Ex. 968 tended to provide a clear formula.

Example 5

This example further illustrates the relatively low irritationassociated with compositions of the present invention according tocertain embodiments.

TABLE 7 Ex. AA Ex. BB Trade Name INCI name w/w % w/w % Ex 968 (30%)Acrylates copolymer 6.000 7.5 Cedepal TD-403 (30%) Sodium tridecethsulfate 16.000 16.000 Tegobetaine L-7V (30%) Cocamidopropyl betaine22.500 22.500 Altas G-4280 (70%) PEG-80 Sorbitan laurate 2.000 2.000Versene 100 XL Tetrasodium EDTA 0.250 0.250 Promidium LTS PEG 150Disetearate & 0.750 0.750 PPG-2 Hydroxyethyl Cocamide Fragrance TAH23194 Frangrance 0.275 0.275 Tween 20 Polysorbate 20 0.500 0.500 Celquat230M Polyquaternium 10 0.1425 0.1425 Versene 100 XL Tetrasodium EDTA0.250 0.250 Sharomix 824 Phenoxyethanol & parabens 0.600 0.600 Yellow#10 FD&C Yellow #10 0.240 0.240 (0.1% solution) Orange #4 FD&C Orange #40.220 0.220 (0.1% solution) 20% NaOH Sodium hydroxide qs qs Deionizedwater Water qs qs

TABLE 8 Example Ex. 968 added TEP Example AA 6.0% 2.9 Example BB 7.5%3.5

Compositions AA and BB are made in accord with the amounts in Table 7.As seen in Table 8, Example AA (with Ex. 968 at 7.5 wt %) has asignificantly higher TEP score than Example BB (with Ex. 968 at 7.5 wt%). Even at polymer levels above 6.0 wt %, increased levels of Ex. 968results in significant improvement in the mildness of the formula.

1. A personal care composition comprising a low molecular weight, non-crosslinked, linear acrylic copolymer and at least one surfactant selected from the group consisting of anionic surfactants, amphoteric surfactants, nonionic surfactants and combinations of two or more thereof.
 2. The composition of claim 1 having a clarity of at least about 90% transmittance.
 3. The composition of claim 1 having a clarity of at least about 95% transmittance.
 4. The composition of claim 1 having a turbidity of less than about 20 NTU.
 5. The composition of claim 1 having a turbidity of less than about 10 NTU.
 6. The composition of claim 1 wherein said copolymer and said at least one surfactant exhibit a C₉₀ that is greater than about 250 mg/L.
 7. The composition of claim 1 wherein said copolymer and said at least one surfactant exhibit a C₉₀ that is greater than about 500 mg/L.
 8. The composition of claim 1 wherein said copolymer has a number average molecular weight of from about 5,000 to about 80,000.
 9. The composition of claim 1 wherein said copolymer has a number average molecular weight of from about 10,000 to about 50,000.
 10. The composition of claim 1 wherein said copolymer is derived from at least one first monomeric component selected from the group consisting of α,β-ethylenically unsaturated monomers containing at least one carboxylic acid group, and at least one second monomeric component selected from the group consisting of α,β-ethylenically unsaturated non-acid monomers containing a C₁ to C₉ alkyl group.
 11. The composition of claim 10 wherein said copolymer has a viscosity of 500 mPa·s or less at a 5 wt. % polymer solids concentration in deionized water and neutralized to pH 7 with an 18 wt. % NaOH solution.
 12. The composition of claim 11 wherein said first monomeric component is selected from (meth)acrylic acid, itaconic acid, citraconic acid, maleic acid, fumaric acid, crotonic acid, aconitic acid, and mixtures of two or more thereof.
 13. The composition of claim 11 wherein said second monomeric component is selected from a monomer represented by the formula: CH₂═CRX wherein R is hydrogen or methyl; X is —C(O)OR¹ or —OC(O)R²; R¹ is linear or branched C₁ to C₉ alkyl; and R² is hydrogen or linear or branched C₁ to C₉ alkyl.
 14. The composition of claim 11 wherein said second monomeric component is selected from the group consisting of ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, vinyl acetate, 1-methylvinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl pivalate, vinyl neodecanoate, and mixtures of two or more thereof.
 15. The composition of claim 11 wherein said first monomeric component is selected from the group consisting of (meth)acrylic acid and said second monomeric component is selected from the group consisting of at least one C₁ to C₉ alkyl (meth)acrylate.
 16. The composition of claim 11 wherein the ratio of said first monomer component to said second monomer component ranges from about 20:80 wt. % to about 50:50 (wt./wt.) based on the total weight of the monomers in the polymerization medium.
 17. A personal care composition comprising a non-crosslinked, linear acrylic copolymer derived from at least one monomeric component selected from the group consisting of α,β-ethylenically unsaturated monomers containing at least one carboxylic acid group and at least one monomeric component selected from the group consisting of α,β-ethylenically unsaturated non-acid monomers containing a C₁ to C₉ alkyl group, and at least one surfactant selected from the group consisting of anionic surfactants, amphoteric surfactants, and combinations of two or more thereof, wherein said composition has a clarity of at least about 90% transmittance and said copolymer and said at least one surfactant exhibit a C₉₀ that is greater than about 500 mg/L.
 18. A personal care product comprising a composition of claim
 1. 19. The personal care product of claim 13 wherein said product is selected from the group consisting of shampoos, washes, baths, gels, lotions, creams, wipes, and combinations of two or more thereof.
 20. A method of cleansing at least a portion of the human body comprising applying a composition of claim 1 to the body. 